Re: Optimal amp load for SHL5

Alan -

Thanks for the reply and directing me to the info on the site. The amp is indeed tube. I'm certainly not inclined to spend $ without reason, but my hope was that I could extract more from the amp (I've been told as much as 2-2.5db), so that on those days when I want to listen at, say, two levels above normal, I wouldn't experience that excessive loudness that makes me think that the amp could be clipping. One other question for you: on the web link to the impedance information on the SHL5, it states "The electrical load impedance and phase curve of Super HL5 which confirms that it has an easy load and suits almost all amplifiers." Could you explain this for me?

Re: Optimal amp load for SHL5

The two impedance charts have to be read together. What they tell is that the electrical resistance never drops very low (the left chart) and that as the electrical phase angle (right chart) hovers around zero degrees. This says, taken together, that the speaker presents a very benign load to the amplifier.

I demonstrated to Walter Swanbon (of Harbeth USA) when he was here last week that during the design of a Harbeth speaker crossover on my simulator I keep two screens open simultaneously. One shows me the predicted frequency response of that crossover plus those drivers and box and the other shows me the two electrical impedance charts. So, every time I change a component in the crossover model I can instantly see if it has an unwelcome effect on the load presented to the amplifier. If it does, I abandon that line of design, and find another solution even if that takes much longer and a lot of head banging.

As I have said before, it is of paramount importance to me that all Harbeth speakers present a relatively benign electrical load to the amplifier. We are a commercial business with the desire to sell more and to avoid after-care issues relating to amplifiers. That means, quite simply, Harbeth speakers will work with any and every credible hifi amplifier that exists.

The Monitor 40 is a rather special case. The load was more difficult but the new upcoming M40 has been comprehensively redesigned to be no more difficult than the SHL5.

Re: Optimal amp load for SHL5

Looking at the left chart, I'm going to guess that at the two times the resistance drops to about 4-5 ohms, this would present a challenge to the amp if I rewired it for 8 ohms - even with a good portion of the speakers' resistance being well above 10 ohms over the frequency range. A good lesson for me here is that the nominal impedance figure for any speaker doesn't come close to capturing the its "real" resistance characteristics.

An aside on the issue of amp power: I have an old 125 watt receiver that powers the P3es2s, having formally used a 30 wpc amp with them. I find the higher powered receiver makes them come to life quite a bit more, though I am mindful of your Bentley analogy, and hit the accelerator carefully!

Thanks again for the thoughts. Think I'm inclined to leave well enough alone...

Electrical load across an entire country ...

Yes, that's how to read the charts. But not only read the impedance minima (say, 4 or 5 ohms as you found) but note the frequencies at which you find those on the x horizontal axis. Then look across to the phase chart and see what the electrical phase would be encountered at those impedance minima. If the phase is say, plus or minus 30 degrees then that can be considered an easy load. You'll find that to be true of all Harbeths.

The issue is quite similar to that of the load presented to the National Grid's power stations which distributes power to the country to all the electrical equipment in our homes, offices and factories. From the viewpoint of the power station looking out down the wires to the load we are drawing, much of the load is driving motors - in fridges, airconditioners, vacuums, heating pumps, fans etc..

Motors are inductive loads - unlike an electric kettle which is a purely resistive load, a motor presents a 'phasey' load and it does not couple efficiently to the National Grid. Nor do fluorescent strip lights which have a large coil inside as part of their firing circuit offset by a capacitor to cancel the coil and make the load more resistive. The electricity companies keep a close watch on the phase of the load presented to the power stations and hopefully, it all balances out giving a close to zero phase load which makes for efficient production of electricity. However, where a large housing or industrial estate draw from a common point, the electricity supply company will determine how phasey the load is and apply appropriate correction, typically with banks of huge high power capacitors hidden behind safety barriers.

So the issues we face between amplifier and speaker load are mirrored in the national distribution of electricity.

SHL5 supertweeter etc.

Hi Alan,
I was hoping that you might be able to clear some question about the new SHL-5 30th Aniversary OFC model. I heard from my local dealer is the OFC cable use within the speaker box. Is there anything change?

Does the SHL5 OFC use the same Radial Driver as the the Current C7ES3?

Apart from OFC Cables is there any other changes?

Does it use the same tweeter as the current C7ES3 or C7ES2?

For the SuperTweeter what is the maximum high extension (kHz) physically it can produce before it breakup?

What is the crossover frequency for the main driver to tweeter and super tweeter?

Thanks a million... I am currently using a C7ES2 and thinking of upgrading into the SHL5 OFC

SHL5 supertweeter etc.

2. The OFC cable and the metal 30th Anniversary Edition label are the main changes.

3. No; the Super HL5 uses the tweeter that has been used in the HL5/SuperHL5 for many years. The Compact tweeter has never been used in the HL5/Super HL5.

4/5. The supertweeter augments the main tweeter above about 15kHz up to beyond 20kHz and there is no electrical crossover to the super tweeter from the main tweeter. The supertweeter is driven from a crossover section which ensures that it only handles the very highest frequencies.

If you enjoy your Compact 7ES2, you may wish to consider the C7ES3 which is also available as a 30th Anniversary OFC version and has been very successful for Harbeth this last year.

SHL5 supertweeter etc.

To answer your question about 30th Anniversary OFC Super HL5:
4/5. The supertweeter augments the main tweeter above about 15kHz up to beyond 20kHz and there is no electrical crossover to the super tweeter from the main tweeter. The supertweeter is driven from a crossover section which ensures that it only handles the very highest frequencies.

I am really into extreme high frequency response as I love clear and unobstructed as I chose SACD over normal CD (if avalaible) and LP using Low output MC to get high extension clear. Even my amp support well above 20kHz (not too sure but I think it is in a range of 50kHz). I understand from your explaination it the crossover doesn't limit the high frequency but what is the theoretical limit of the SHL5 Supertweeter can handle?

For the Main driver to the main tweeter what is the crossover cutover Hz?

Thanks for the heads up for Compact 7ES3 OFC model - You pretty much help me make my decision in going for the SHL5 with the OFC due to the supertweeter.

SHL5 supertweeter

Concerning the supertweeter in the SHL5 .... I've selected the supertweeter so that it gently rolls off as the frequency extends. I consider that this is a safe design strategy because you do not want to find yourself in a situation where, say, surface clicks on a record cause untamed oscillations of the tiny diaphragm. That would be extremely irritating and tiring to listen to. Too much or too extended extreme HF is rather like driving on a bumpy road with 'sports' suspension where you feel every small bump. My approach is more like the 'comfort' setting where you just glide along enjoying the musical journey.

Re: SHL5 supertweeter

Thanks Alan. I have change my Compact 7ES2 to the 30th Anniversary SHL-5 OFC and it blew me away... it is clear extension and deeper bass note. Initially I was afraid of bass boom in my smallish hall... but it turn out alright - a bit of bass hump - need better placement and some room treatment. My local harbeth dealer was very helpful in resolving issues that I had.

Thanks for a wonderful product and I am looking forward hear the M40.1

Cheers.

p.s. I understand that you were in the local forum replying to the masses to clarify stuff... Personally I have been attack (through words) by another forumer for purchasing it from local harbeth dealer due to the price difference. I understand and fully appreciate the clarification of the pricing difference. To me if I gotten a good service and ease of mind in purchasing a product - even though it is slightly expensive I will pay for it for the above reason.

Originally Posted by A.S.

Concerning the supertweeter in the SHL5 .... I've selected the supertweeter so that it gently rolls off as the frequency extends. I consider that this is a safe design strategy because you do not want to find yourself in a situation where, say, surface clicks on a record cause untamed oscillations of the tiny diaphragm. That would be extremely irritating and tiring to listen to. Too much or too extended extreme HF is rather like driving on a bumpy road with 'sports' suspension where you feel every small bump. My approach is more like the 'comfort' setting where you just glide along enjoying the musical journey.

Re: Harbeth SHL5 specific

My room size is actually quite small 4 meters X 5.5 meters - I use the long side of the room. Thanks for your recommendation - I was intially afraid that the SHL-5 will be too big in my room but it was fine and just a bit of bass gain in the 40Hz region I guess... may need further room treatment to fix the issue.

Cheers.

Originally Posted by keithwwk

Hi Soundbyte,
Very happy to read you feel happy with your C7 to SHL5 upgrade...bcos I will doing that soon too..

Re: Harbeth SHL5 specific

My room is slightly smaller than yours, which is 3.5 x 5.5....now I am start to worry if e 5 will boom even more than yours....my room is closed room..hm..worry now..

Originally Posted by Soundbyte

My room size is actually quite small 4 meters X 5.5 meters - I use the long side of the room. Thanks for your recommendation - I was intially afraid that the SHL-5 will be too big in my room but it was fine and just a bit of bass gain in the 40Hz region I guess... may need further room treatment to fix the issue.

Re: Harbeth SHL5 specific

Hi to everybody,
My room has exactly the same dimensions with Keith's room. Yes I have some boom occasionally, depending on music played. I also have to face and treat the problem. My positioning of the SHL5s is of course along the narrow dimension at 1m. from back wall, 55 cm. from side walls, about 10o toed-in, listening spot at about 2,5-3m. away. Speaker clearance from woofer to woofer is about 2.5m. Stands, with very good isolation from both the hardfloor and from the speakers as well, are about 42 cm tall custom made from solid wood. Any suggestions to tame the bass?
Thanks and cheers from Athens,
Thanos

Re: Harbeth SHL5 specific

Hi Thanos,
I will getting a SHL5 soon..your post is really important to me now..
My current old C7 was place along the short wall..I did faced some bass problems and caused overal sound all blurr (overal stil great sound) and bass lack punch.. Now, I placed it along the long wall, the overal sound is pretty impressive including the bass, very punchy and big scale. Of cos, I plan to place my SHL5 along the long wall too...You may try it now...and pls tell me if it work for you...

Re: Harbeth SHL5 specific

Originally Posted by keithwwk

Hi Thanos,
I will getting a SHL5 soon..your post is really important to me now..
My current old C7 was place along the short wall..I did faced some bass problems and caused overal sound all blurr (overal stil great sound) and bass lack punch.. Now, I placed it along the long wall, the overal sound is pretty impressive including the bass, very punchy and big scale. Of cos, I plan to place my SHL5 along the long wall too...You may try it now...and pls tell me if it work for you...

Keithwwk... don't worry too much... just look at my picture below.

Thanos is right it only happens to some music not all... so now I am look for a nice thick carpet and some material to take care of corners....

Re: Harbeth SHL5 specific

Thanos is right it only happens to some music not all... so now I am look for a nice thick carpet and some material to take care of corners....

Cheers

Hi bro, wow nice pic of your new SHL-5.....i reckon a rug placed in the middle of your living room should improve things. Btw, i really like the addition of 30th anniversary sticker with Alan Shaw's signature on the rear...looking forward to visiting you soon...the SHL-5 is a superb spk capable of giving you lashings & lashings of pure musical enjoyment!